Using MR cholangiopancreatography to reveal anomalous pancreaticobiliary ductal union in infants and children with choledochal cysts.

Objective: The purpose of this study was to determine whether MR cholangiopancreatography can accurately depict anomalous pancreaticobiliary ductal union in children with choledochal cysts.
Subjects and Methods: Twenty children (age range, 1 month-13 years; mean age, 4.6 years; all girls) who were diagnosed with choledochal cyst by sonography underwent MR cholangiopancreatography with a single-shot fast spin-echo sequence. The type of choledochal cyst and anomalous pancreaticobiliary ductal union were characterized on the basis of MR cholangiopancreatographic findings and were compared with the finding of intraoperative cholangiography.
Results: The type of choledochal cyst (type Ia, n = 4; type Ic, n = 7; type IVa, n = 7; type IVb, n = 2) determined on MR cholangiopancreatography correlated with that identified on intraoperative cholangiography in each patient. Anomalous pancreaticobiliary ductal union was detected by MR cholangiopancreatography and intraoperative cholangiography in 12 (60%) and 16 (80%) of 20 patients, respectively. The types of anomalous pancreaticobiliary ductal union as determined on MR cholangiopancreatography (type A, n = 2; type B, n = 7; type C, n = 3) were concordant with those of intraoperative cholangiography in 11 of 12 patients. In five of eight patients with choledochal cyst (type Ia, n = 1; type IVa, n = 5; type IVb, n = 2) in whom MR cholangiopancreatography could not depict anomalous pancreaticobiliary ductal union, anomalous pancreaticobiliary ductal union was documented on intraoperative cholangiography that was performed after choledochal cyst resection.
Conclusion: MR cholangiopancreatography provides diagnostic information about anomalous pancreaticobiliary ductal union in children with choledochal cyst.